Fourteen-speed planetary transmission



Sept. 15, 1953 c. E. scHoU SPEED PLANETARY TRANSMISSION FOURTEEN- 7 Sheets-Sheet l Filed Oct. 24, 1949 QHIII 1 1 N TT] MM.

ATTO R N EY Sept. 15, 1953 c. E. scHOU 2,651,950

FoURTEEN-SPEED PLANETARY TRANSMISSION Filed oet. 24, 1949 '7 sheets-sheet 2 Sept. l5, 1953 c. E. scHou 2,651,950

F'OURTEEN-SPEED PLANETARY TRANSMISSION Filed oct. 24, 1949 7 sheets-sheet 3 gwuem/tov @mf @wdm,

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INVENTOR BWM MW ATTORNEY Sept. 15, 1953 c. E. scr-lou FOURTEEN-SPEED PLANETARY TRANSMISSION Filed Oct. 24, 1949 7 Sheets-Sheet 5 ATTORNEY Sept. 15, 1953 c. E. scHoU FOURTEE-SPEED PLANETARY TRANSMISSION Filed OCT.. 24, 1949 7 Sheets-Sheet 6 ATTOR N EY Sept. l5, 1953 c. E. scHoU 2,651,950

FoURTEEN-SPEED PLANETARY TRANSMISSION Filed Oct. 24, 1949 7 Sheets-Sheet 7 [E] man nessun: en E DRAM on.

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.K P Q z /Q M new Mo@ latented Sept. 15, 1953 FOURTEEN- SPEED PLANETAR TRANSMISSION Carl Einar Schou, Seattle, Wash., assignor to Pacific Car and Foundry Company, Renton, Wash.

Application October 24, 1949, Serial No. 123,267

8 Claims.

rIhis invention relates to improvements in a pre-selected planetary transmission controlled from a multiple clutch assembly.

One of the objects of the invention is to provide a speed reducing unit for supplying each of the speeds of a pre-selected planetary transmission to a pre-determined ratio.

A further object of the invention is to provide in a pre-selected planetary transmission, controlled from a multiple clutch assembly, with a speed Varying unit for changing each of the speeds of the transmission to a pre-determined ratio and in which the speed varying unit is capable of cooperating at any and all speeds, and without reduction of the speed of the input shaft.

Another feature of this invention is to provide a speed reducing unit for changing the speeds of a main transmission in which a construction and arrangement of parts is provided wherein association between the speed reducing unit and the main planetary transmission can be accomplished at all speeds Without synchronization between the main transmission and the auxiliary speed reducing transmission.

A still further object of the invention resides in the use of the main or unit transmission for synchronizing the drive between the same and the auxiliary speed reducing transmission without affecting the speed of the motor.

A further object accomplished by the present invention is the provision of synchronizing means between a main unit transmission and an auxiliary transmission in which the overrunning of the vehicle at the time the power is disconnected is utilized in synchronizing the transmission shafts.

More specifically, this invention comprehends a plurality of transmission assemblies, one of which is capable of pre-selection independent of motor speed, and the other of which is capable of cooperation with the first transmission without variation of the motor speed, and by control of the first transmission through shifting to the neutral position, the driven shaft is synchronized with the main transmission shaft through the use of a planetary unit and the reduction of the speed of the main transmission shaft for synchronization is multiplied in accordance with the planetary structure.

Other objects of this invention Will more clearly hereinafter appear by reference to the accompanying drawings and specification, wherein like characters of reference designate corresponding parts throughout the several views, in which:

Fig. 1 is a longitudinal section through a unit transmission and multiple clutch assembly with the speed reducing unit associated therewith;

Fig. 2 is a vertical section through the clutch structure;

Fig. 3 is an end view partly in section of the clutch assembly;

Fig. i is an enlarged longitudinal section of the speed reducing unit and clutch therefor;

5 is a diagrammatic view of the operating system for the unit transmission;

Fig. 6 is an enlarged vertical section through a ptortion of the clutch of the speed reducing um Fig. '7 is a diagrammatic view of the speed reducing unit clutch actuating means;

Fig. 8 is a view illustrating one position of the clutch for the speed reducing unit and the operating mechanism therefor;

Fig. 9 is a further view showing an alternate position of the clutch of the speed reducing unit and operating means therefor;

Fig. 10 is a longitudinal section showing the valve control for the clutch of the speed reducing unit; and

Fig. l1 is a schedule of operation.

Referring to Fig. l, the multiple clutch assembly and the main or unit transmission are of the type shown in my co-pending applications Ser. No. 2,293, filed January 14, 1948 and Ser. No. 82,195, led March 18, 1949.

Referring now to the clutch structure, there is illustrated in Fig. 2 three driven shafts indicated by reference characters A, B, and C, these shafts being concentric, with the central shaft A proJecting beyond the end of the intermediate hollow shaft B and the end of this intermediate hollow shaft projecting outwardly from the end of the hollow outer shaft C, the exposed portions of each shaft providing a support for the spiders d, b, and c which carry the driven discs l0, l! and l2, respectively. The spiders a, b, and o are suitably splined to the ends of the shafts A, B, and C as is conventional in such instances. Also the discs le, ll and i2 are generally or" conventional form.

The shafts A, B, and C are arranged in and confined by the tubular housing D, this housing l) being provided with annular flange I4 to which 1s secured as by rivets I5, the slotted concave housing plate I6. The slots in the housing may be of any form or design to permit essential coolmg by air flow and are indicated by the reference character l1. The housing embodies a cylinder structure enclosing the clutch units, this cylinder structure being fabricated to embody supporting means for the outer backing plates I8-I 8 for the two inner clutch assemblies, the outer backing plate for the clutch Il] being provided by the flywheel as indicated at I9. Arranged alternately of the backing plates I are the inner fixed annular concave partitions which are located within each of the three fluid chambers defined by the diaphragms. The backing plates I8 and I9 and the fixed concave inner backing plates or partitions 120 are positioned and secured by elongated bolts 2I suitably spaced about the marginal edge of the casing assembly, the bolts extending into and supporting the casing from the iiywheel I9. It will be noted that each of the backing plates I have lateral ilange portions I8a tending to elongate the housing. The housing wall I6 has its'marginal edge 22- flattened to receive the head 23 of the elongated bolts 2l so that the parts can be clamped together. Also clamped between the alternate backing plates and partitions are the metallic concave diaphragms 2 5, these plates having their outer marginal vedges sealed by rubber gaskets 2 ,ii to; prevent leakage at their outer ends. The inner ends of the diaphragms 25 are xed in annular grooves formed at the outer faces of the ring or piston elements 21, seals or packing rings.. 2:8, being provided between each of the plates and the abutting wall of the annular projection 29 of the pistons to eiect a seal at this endvof the plates and to provide between each pair of diaphragms `25 a sealed chamber which is partitioned by the annular concave backing element 20. The. diaphragms 25 will preferably be of thel type of the Belleville washer and may be made from suitable steel alloy or from copper or any other desired material capable of providing the requisitei factors including inherent relatively lstii resiliency which will result in the diaphragins normally retaining or assuming a fixed predetermined position while permitting thse diaphragns toshift together under press'ure `froma suitable fluid solution as will be hereinafter more fully. described.

TheJ inner annular edge of the backingl plates 2p, areeachI provided with a suitable seal 30 which engag'eS adjacent outer annular face of the exlt'enSQn 29. y'n'nular piston 21 to provide a su" 'able sealing relation therebetween. Each of the diaphragms 2,51 oi each` of the fluid chamber units of eachsclutch actuating assembly is so spa ed, asY to provide' `at each side of the inner b aI in'g partition 2D chambers of substantially the same" capacity. Spring clips 24a are interdfa'ji predetermined positions between the fic ve'4 clutch pressure plates 24` and the inner ring pisto'nsf]V of the fluid chambers to assist in maintaining these clutch plates 24 in position and to function as anti-rattling devices. The active pressure plates ,2 IIA are each slidably mounted on the outer casing by a number of spaced pins, oneof which isvindicated by reference character 45, see Fig.AY 1'. These pins are pressed into the outer casing and nt into transverse slots in the outer peripheral edge of each. of the pressure plates 24, The pressure plates 24 consequently canfmove longitudinally as shown in Fig. l of thedrawings. 'The grooves 4B which are milled in the outer peripheral edge of the pressure plates cooperate with the square heads l5EL of the pins, these square heads of the pins riding in the milled groove and keeping the pressure plates-aligned and permitting their longitudinal movement'. *The 'limitation of movement of each ofnthepressureplates is determinedby the dia- 4 phragms on one side and the clutch plate on the other. Normally the clearance between the clutch plates I0, Il. and I2, and pressure plates 24 is preferably in the order of 12. The movement of the diaphragm to cause clutch engagement of the plate need not be more than elf.

Inasmuch as each of the chambers provided at each side of the backing plate 20 is substantially of the same capacity and with the same pressure areas and is adapted to contain uid from the same source and normally at the same pressure, it will be apparent that at high speed r0- tation the clutch will remain neutral. This is clue tothe fact that the centrifugal forces, acting on they fiuid in the chambers, creates energy which will act in all directions inside of the chambers, and these centrifugal forces are in equilibrium under all conditions and regardless of speed. The static condition created by centrifugal f orce is subject to unbalance by a variation of the pressure in the high pressure side of the clutch assembly, this unbalance creating the operating pressure provided in the structure forl movement of the active pressure plates of the clutch assemblies. It will be noted that the size of the low pressure chamber will provide sufoient clearance to permit extra movement compensating for clutch wear.

The operating iiuid is provided in the high pressure side of each chamber by suitable conduits d, three 'in' number, which feed the high pressure side of the clutches and an additional feed pipe which normally supplies low pressure to the low pressure side of each of the fluid chambers to maintain a constant volume in this low side. These conduits 43 extend into the Wall of the annular chamber or hub D to deliver the fluid to the individual clutch assemblies through ports which are drilledA into the clutch casing structure as at lil. lnr Fig. 3 which is a transverse section, the conduits 4I! are illustrated with the hub ports tea, 4th, andl 49C shown in section for communi-y cating with clutches I7-, 2 and 3. The discharge from hubl portV 40a discharging through the connection 4I in the clutch casing and conducting fluid into the outer clutch I and between the outer clutch plate andthe backing plate. Each uid chamber as comprehended by the fixed backing plates 20' andthe diaphragms 25' are providedwith a high pressurel inlet 42 which will be supplied with a nuilfunder pressure, for instance, approximating 13O3lbs. The opposite chamber in each of the fluidmotors is provided with suitable communications indicated in dotted line at t3 to normally supply fluid atV low pressure, say 60 lbs., to the low pressure side of the cylinder. The low pressure side of each of the cylinders is normally in communication with the same source of supply andAsame-ducts so that the low pressure side "of each chamber remains with a normally constant pressure substantially below the pressure which may be applied to the cylinder at its high pressure sides through ducts 42.

As previously stated: the diaphragms, 25 are so constructed as to provide the necessary tension to normally maintain the piston or ring 21 at approximately-the position illustrated in Fig. 1', in which position theclutches are disengaged. This normal position of the diaphragmswhich is maintained by the inherent tension of the diaphragm structuresL provides in cooperation with medial backing plates 20, the high and low pressure chambers. The .pressurechambers may contain low. pressure. fluidat all times vsothat the operationr of. the; various clutches is4 accomplished by overcoming the pressure in the low pressure chamber, plus the inherent spring reaction of the plates due to their structure. The diaphragms for the low pressure chamber are normally free of contact of the pressure plates 20 and therefore the pressure in the low pressure chamber is not sufficient to distort the low pressure diaphragm but only suiiicient to maintain both the diaphragms in their normal unsprung position. The pressure on the diaphragms is not determined by the volume between the diaphragms and the backing plate but only by the area in the longitudinal projection. Thus it will be seen that while both the low and high pressure chambers may be capable of substantially the same volume, one may contain less volume, but this is not important because the actual working pressures as defined by the pressure areas are in the direction of the longitudinal axis or horizontally of the structure. In order that the effective pressure in both the high and low pressure chambers may be accordingly provided, the arrangement is such that the pressure plate faces in both the high and low pressure chambers never snugly engage the diaphragms so that portion of the diaphragm area is never blocked against pressure action. This is obviously provided for by the structure of the parts and the selection of material from which the diaphragms are made, this material, as heretofore stated, being inherently sufliciently resilient that the diaphragms maintain their normal predetermined concave shape at all times including the time of their shifting. The shape of the diaphragms is fairly critical and may affect the successful operation of the device and of the pressure which acts upon the clutch and thus this feature of the development is of prime importance. In addition, inasmuch as the operation of the diaphragms corresponds substantially to the movement of the piston in that the direction of the force is constant, the nature of the material used, as well as the shape of the diaphragm, and its thickness are al1 features of paramount importance.

An annular bead 2lD is arranged medially of each pressure plate 24 at its outer face and against which the adjacent diaphragm or pressure plate operates. When high pressure fluid is forced in between the adjacent diaphragm and the enclosed partition or backing plate 20, the

vinner ring 2l' which seals the inner peripheral edges lof the pair of diaphragms will move the diaphragms toward the adjacent active plate 24, which in turn will be forced against one of the driven members l0, Il, or l2 in accordance with the clutch assembly which is in operation.

The diaphragms, which as heretofore stated, are of the Belleville washer type are normally concave and maintain their concave shape even under pressure from the fluid and during the course `of operation. In other words, the concave pair of diaphragms 25 of each fluid chamber shift as a unit and in concave form carrying with them the inner ring structure 21 Which is suitably sealed by a gasket 30 with the inner periphery of the partition 20. The rings 21 of each fluid motor will move longitudinally when high pressure is applied and will move with the diaphragms toward the medial adjacent bead 24b of the active plates 2li. Due to the structure and the assembly of the clutch the force acts on the pressure plate always in a horizontal direction or in the direction of the axis of the shaft, thus preventing canning or unbalancing of the pressure plates.

In order to balance this condition and prevent 6 any self-injury on the clutch system, there is provided a low pressure chamber at the opposite side of the pressure plates which norm-ally has substantially the same capacity as the high pressure chamber. If both the high and 10W pressure chambers are filled with oil, and it is spun around, then the centrifugal forces within the system are in equilibrium. This construction has a tremendous effect on the success of the operation of the clutch. 'I'he uid pressure itself, as applied to the active clutch plate, unbalances the static condition and represents the operating pressure. In order to apply pressure on the clutch you will have to apply pressure through the control lines 4i) which lead into the high pressure chambers. A separate oil line connects the high pressure chamber of each individual clutch. There is a normal low pressure line to the low pressure side of each clutch which together with the leakage about the inner ring establishes low pressure chambers in each clutch .at all times including that period when high pres-- sure is applied to the high pressure chamber tooperate the associated clutch. The operation of each clutch must therefore be accomplished by overcoming the pressure in the low pressure chamber. The high and low pressure chambers; have the same areas in the transverse sections. The longitudinal acting pressure caused by centrifugal force acting upon fluid is always in equi` librium regardless of revolving speed. The ef fective operating pressure is equal to pressure irn the high pressure chamber minus pressure in the low pressure chamber. If all the fluid chambers of each of the clutches were full of fluid at all times, these clutch plates would be balanced at each side of the inner pressure plate or partition 2Q. The diaphragm has a certain tension which normally keeps the ring moved in the location that is shown in the sketch with the low and high pressure chambers of substantially equal capacity. It will be noted that the shape of each of the diaphragms is such that these diaphragms are maintained in such a position that the feed lines to the low pressure chambers are normally open to receive fluid.

The diaphragm for the low pressure chamber, 'it will be noted, is normally free of contact of the pressure plate and therefore the pressure at any one point in the low pressure cham-ber is not sufficient to distort the low Ipressure diaphragm 4but only sufficient to maintain both of the diaphragms in their normal unsprung position. The pressures on the ldiaphragms are not determined by the volume between the diaphragm and the backing plate but only by the area in the longitudinal projection. Both of the pressure chambers (low and high pressure) are substantially the same volume, but this is not important because the actual Working pressures are in the direction of the longitudinal axis of the structure or horizontally of the structure.

The gear associated with the present clutch assembly involves three planetary gear trains, with the various speed ratios engaged hydraulically by the three disc clutches heretofore described, and with the association of three friction drums or brakes connected into and with the planetary gear trains. The transmission is of the general type of my prior application Ser. No. 2,293, led January 14, 1948, and a single shift lever or gear selector is employed and may be located at any desired place, such as on the steering column or Wherever is convenient to the driver. The control will normally include nine positions, one for each of the seven forward speeds and a control for neutral and reverse. As heretofore described, the three friction clutches which are mounted on the flywheel can be independently operated and are actuated by fluid pressure provided Iby a pump PP, preferably located in the transmission sump. The general operation of the three planetary trains and the associated clutch and brakes to procure the flow of torque at the various speed ratios will be substantially as follows:

rlhe first speed is ob-tained by engaging the second or intermediate clutch which transmits the torque to the sun gear 60 of the first planetary train. The brake band E! is hydraulically applied to the drum `(i2 which holds the ring gear 63 stationary. The planet carrier 84, which is the driven member of this first gear train, is integral with the driving ring gear E of the third planetary gear train. In this first speed operation the brake @E is applied to the brake drum El to lock the latter and to hold the sun gear 68 stationary. 'Ihe planet carrier B9 of the third planetary gear train is the driven member of the third planetary unit and is integral with the output shaft lil. The reduction of the first gear train is 3 1 and in the third gear train it is 1.5-1 so that the total reduction is 4.5-1.

To secure the second speed, the first clutch is engaged directly to the flywheel land the torque is transmitted through the main shaft A to the sun gear '.'2 of the third planetary unit. The ring gear S5 of the third planetary unit which is splined to the carrier 64 of the first planetary unit is held stationary by the application of the friction band or brakes 6I and i3 to lock the drums 62 and 1l of the rst and second assemblies and through the locking of these drums loci: vthe ring gear 63 and the sun gear 60. This 4combination produces the ratio 3.00-1.

In producing the third speed the third or inner clutch is engaged to the flywheel by actuation of the associated fluid motor and rotates the ring gear `S3 of the first planetary gear train. The sun gear of the first gear train, which is splined to the clutch B, rotates the carrier 64 of the first gear train and the ring gear 85 of the third planetary unit, the rotation being 2/3 the speed of the crankshaft. In the third gear train the sun gear 68 is held stationary by locking the drum B1 by applying the brake 85 through fluid pressure. The reduction in this case is equal in the first and third gear trains so that the total reduction is 2.25-1.

In the fourth speed, the first and second clutches are engaged to the flywheel and part of the torque is transmitted from the second clutch to the sun gear 60 in the rst planetary train. The rst drum G2 is locked by the application of the brake and the carrier 64 is then rotating 1/3l of the speed of the crankshaft, The carrier 64 and the output shaft driven thereby is splined to the ring gear 55 of the third gear train, and thus the torque is here combined with the remainder of the torque which is transmitted from the first clutch to the sun gear 'l2 of the third planetary train. This produces a reduction of approximately 1.80-1.

To obtain the fth speed, the second and third clutches are engaged and these in turn revolve the first planetary gear train and also the ring gear 65 of the third gear train at engine speed. The third drum 61 is held stationary by application of the brake 66 and the carrier on the output shaft 10 revolves with a reduction or speed equal to 1.50-1.

In the sixth speed vthe clutches l and 3 are' engaged to the flywheel and part of the torque is transmitted to the ring gear 63 of the first gear train. The intermediate or second drum H is held stationary by the application of the brake 13 and the ring gear 63, splined to the carrier of the first gear train, revolves at the speed of /g, the engine R. P. M. The remainder of the torque is transmitted from the rst clutch to the sun gear 12 of the third gear train assembly and is in the third gear train combined with the torque transmitted to the ring gear of the same unit. The overall reduction is 1286-1.

To obtain the seventh speed all three of the clutches are engaged and torque is transmitted to the sun gear 60 and the ring gear 63 of the first planetary unit. Consequently the ring gear being splined to the carrier 64 is revolving at engine speed. The remainder of the torque is transmitted directly from the No. l clutch to the sun gear 'i2 of the third gear train. As a result, all members of the planetary system are thus revolving at the same speed and the ratio is 1.00-1.

In reversing, the first clutch is engaged to the flywheel and ring gear 15 is held stationary. rEhe torque is transmitted to sun gear 'l2 of the third planetary gear train. Here torque is divided, part of it being applied to planet carrier 69, the remainder of the ring gear 55 which is connected to sun pinion 16 in the second planetary assembly. That part of the torque which is app-lied to planet carrier 55 is combined again with the remainder of torque which passes from ring gear 55 through reversing gear sun pinion 'lli to planet carrier TI and thence to output shaft 1li. In this case all three members of the planetary gear rotate, the sun gear 'l2 being the driver while ring gear 55 and planet carrier 'i are the driven members. 'Ihe torque applied to the planet carrier 69 is transmitted directly to the output shaft, while that transmitted to the ring gear G5 is carried to the sun gear I6 of the reversing unit, and after being modified on that unit is transmitted through, the reverse unit planet carrier 'H to output shaft 'l0 to which the planet carrier is made integral. In reverse, two sprags l--l are hydraulically engaged by means of fluid operated pistons 'l with the external teeth of ring gear 15. The reduction in reverse is 4.82-l.

Gear ratios and clutch brake functions Clutches I Brakes Speed Ratio SRQV' #i #2 #s #1 #2 #3 praga Reverse 4.82-1 On Ofi Off Oi Ofi Oil I N@utm1 oir off oir oir ofi ou dit. Ofi 0n Oli 0n Of On Out. On O OI On On Oi Out. Oil Ofi On Oli 0n On Out. On On Ol On Oil Oi Out. O On O11 OH Oil On Out. On O11 Ou Off On Oli Out. On On On Oil Ofi Off Out.

As previously stated, one of the objects of this invention is-to combine with a pre-selected planetary transmission, controlled from a multiple clutch unit, a speed modifying unit for multiplying each of the speeds of the main transmission to a predetermined ratio, in the present assembly 4 to l, with the main transmission capable of cooperation at any speed and without reduction of motor speed. by lowering the main transmission speed.. tovsynch'ronize' with the cooperating part of the auxiliary speed reducing transmission. In the further description of this development, the main transmission, i. e. the preselected planetary transmission controlled by the multiple unit clutch and heretofore described, will be referred to as a unit transmission, while the compounding unit, i. e. the speed reducing unit of Fig. 4 and hereinafter described, will be referred to as the speed reducing transmission.

To accomplish the foregoing the following structure is provided. The reduced longitudinally ribbed portion 30 of the output shaft '|0, of the main transmission, has xed thereon the sun pinion 9| this pinion being retained against outward longitudinal displacement on the reduced end of the shaft 10 by means of the annular stop ring 93 and the lock nut 94 which is threaded on the shaft extremity as at 95 and xed by the lock washer 9E. The reduced extremity 90a of the end portion 90 of shaft '|0 is of true cylindrical form and is provided with a recess in which is seated the packing 98 which seals the end of the chamber 99 formed in the driven stub shaft and in which the cylindrical extremity 90a is positioned. The stub shaft |00 is recessed at its inner end portion and axially thereof to provide the chamber 39 which has radial ports |0| and an axaial reduced bore |02 communicating with radial ports |03. The sun pinion 9| is prevented from having inner longitudinal movement by virtue of the inner race |04 against which it abuts, the inner race |04 cooperating with the balls and the outer race |05, and which form a ball bearing assembly for the outer end portion of shaft 10. This ball bearing assembly is located within the hub |01 of the partition |08, which forms a part of the casing and separates the unit transmission from the auxiliary speed reducing transmission. The planetary pinions H0, which will normally be three in number, are supported in a cage formed by a hub-like exten- 'sion of the stub shaft |00, these planetary pinions being freely rotatable on bearings ||2 arranged about the hollow tubular supports ||3 which are provided with suitable radial ports I I4 for feeding lubricant to the structure. On the tubular supports ||3 are the end stop rings ||5 having thrust washers I5 and outer stop rings as is conventional in structures of this type.

Due to this construction, when the cage rotates carrying with it the pinions |I0, the stub shaft |50 will rotate therewith.

Completing the planetary unit is the ring gear |20 and obviously the planet pinions ||0 rotate between the sun gear 3| and the ring gear |20. The ring gear |20 has inwardly projecting ange |2| which faces against the marginal portion of the iiange |22 of the hub structure |23, this hub structure being mounted on the stub shaft |00 with suitable bearings |24 therebetween. Lubricant is fed from the chamber 99 through radial ports [0i to this hub structure and the same is retained against longitudinal displacement at each end by the stop rings |25 and |2511, the stop ring |25 abutting the shoulder |26 of the hub which is a part of the stub shaft |00. This prevents the hub |23 of the ring gear from having longitudinal movement inward. Longitudinal movement outward obviously is prevented by the stop ring |252L which abuts againstthe inner end portion of the clutch element |26 which is splined on the end portion of the stub shaft |00 by the splines |21. 'Splines |30 are provided on the hub |23 and a longitudinal shiftable clutch and brake element |31 Vis mounted Qn the splines 10 |30 for movement into engagement with the teeth |32 of the fixed clutch element |26 and the teeth |33 formed in the outer face of the inner marginal portion of the partition element |34. Thus the clutch and brake element |3| with the teeth |35 at its inner end and teeth |33 at its outer end is shiftable to the two engaging positions or to an intermediate position, this shifting being accomplished by a fluid piston indicated generally at |40. The fluid piston is generally of tubular form and is provided with an annular inner recess i'li for receiving the outer race |42 of a bearing assembly, which includes the balls |43 and the inner race |44. At each side of the inner race 44 which is positioned medially about the sliding clutch and brake element |3| are the centralizing springs |45 shown more clearly in Fig. 6. These springs are interposed between the shoulder |46 and the stop ring |4'l and the side walls of the inner race S44 of the bearing assembly to normally exert a pressure which retains the piston |40 and the clutch and brake element |3| neutral. The annular piston |40 is provided at its outer end portions with the O-ring seals |50 and 5|, the seal |50 contacting the annular face |52 of the partition element |34 which is machined to produce an annular face for association with the annular piston |40. The O-ring seal |5| is associated with the machined cylinder wall |53, this cylinder wall |53 being of greater diameter than the cylinder wall 52 which necessitates the offsetting of the piston structure at the outer end. for association therewith. By this construction the movement of the piston |40 in the cylinder heretofore defined, and including the cylinder walls |52 and |53, Will result in the shifting of the bearing assembly |42|43|44 and the movement of the sliding clutch and brake element |3| to engage at its inner and outer ends the cooperating faces |32 and |33 of the parts heretofore mentioned, to bring about a predetermined operation. The operation of the piston |45 and its control will be hereinafter more fully described in connection with Figs. 8, 9 and 10. The inner face of the annular piston |40 is sealed at its outer end by the O-ring |54 which is positioned in a groove formed in the annular framing element |55, the latter having a lateral flange |55 which is secured by bolts |51 to the frame section |58 as clearly shown. This annular framing element |58 has its outer portion flanged inwardly as at |59 and is grooved internally and inwardly of its ends at |50 to receive a stop ring Il@ to position the outer race of a bearing assembly, including the balls |22 and the inner race |23, the latter being mounted on the fixed clutch element |25 as shown and being retained thereon by the inner shoulder |14 and the inner end portion |15 of the gear H5, which latter is xed on the outer end portion of the fixed clutch element |25 by the key structure and is driven thereby to operate an accessory, such as a fuel pump, through a suitable worm gear |73. The drive iange is splined on the end of the stub shaft |03 by splines |3| and the hub |82 of this coupling element |80 supports the packing assembly |83 to seal the structure against fluid loss. The drive flange or coupling element |80 is locked against outward displacement by the stop ring which is threaded on the end of the stub shaft 00 by threads |9| and locked in adjusted position by the locking nut 92 having the usual lock pin |93. It will be noted that the partition element |34 is drilled and provided with 1l by-passes |34 which permit the fluid to pass through the ports |85 from the oil chamber |86. The partition structure is pinned in between a flange of the outer casing element |53 and the adjacent end wall portion |81 of the main casing by pins |88. Suitable seals |89 are provided for preventing leakage between the casing sections.

To more readily understand the clutch mechanism reference will first be had to Figs 5 and 7 of the drawings. In Fig. 7 the disclosure is diagrammatic and in this disclosure the sliding clutch and brake element is indicated by reference character |3| with the inner teeth |35 and the outer teeth |35. The sliding clutch and brake element ISI is actuated from a piston ii which shifts the rod |6| to swing the lever |62 on its pivot |63 against the tension of the spaced springs |45 to urge the clutch and brake element ISI to the right or left tosecure the necessary operation. The operating cylinder |40 is supplied normally with pressure from the main hydraulic system amounting to approximately 130 p. s. i. through inlet pipe |54, this pipe opening into one side of the cylinder .and a branch pipe |65 carrying the same iluid pressure opens into the valve chamber |56 where the valve le? is provided to control pressure to the opposite side of the piston |46 through the pipe |58, the operation of valve |61 being by means of an electric motor in which the armature H is subject to energized coils K or L by operation of the switch arms M which supply the necessary current from the current source N as indicated. In Fig. 6 there is an enlarged view representing the detailed structure of the overrunning clutch which is used and illustrated in Fig. 4, this Fig. 6 showing in detail the arrangement and structure of the springs |45 and the association of these springs with respect to the inner raceway |44 of the bearing assembly, which includes the balls |43 and the outer race |42. The teeth |35 and |35 are illustrated together with the association of the coacting faces |33 and |32. The disclosure of Fig. 6 in association with the diagrammatic View of Fig. i will generally explain the actuation of the clutch and its actuating motor and the associated uid operating mechanism, the latter being shown more fully in Figs. 8, 9 and 10.

In Figs. 8, 9 and 10 the control of the auxiliary speed reducing unit by means of the electrically actuated valve is illustrated. Diagrammatically in these figures the source of electric current is illustrated to include the battery N and the switch M, the movement of the switch to the contacts Ma and Mb controlling the current to the coils K and L to operate a solenoid which shifts the valve |67 to supply high pressure cil when required to move the sliding piston |46 to operate the clutch and brake member |3| which engages the teeth |32 or |33 heretofore described see Fig. 6). In Fig. 8 the valve |61 is shown in a position to supply high pressure oil to shift the piston |46 to the left to engage the teeth |33, while in Fig. 9 the valve has been moved by the solenoid to supply fluid to the piston |40 so that the sliding clutch and brake element |3| will move to engage the teeth |32. The travel of the high pressure oil, the drain oil, and the lubricating oil is illustrated in Figs. 8 and 9 in accordance with the chart furnished with these gures.

In Fig. 10 there is a longitudinal section shown in which the coils K and L are illustrated, the coil K actuating the solenoid 7c and the coil L actuating the solenoid to shift the valve li'i to properly register with the control ports P in the cylin- 12 drical valve-chamberQ-to provide fluid through the passage 1|64in1the casing wall, which passage furnishes the fluid tothe annular piston |43 for actuation of the lclutch element |3|.

The unit vtransmission `will be operated in accordance with the 4operation described heretofore, this operation being illustrated in Fig. 5

for the purpose of :presenting a complete under-- standing of the'present development. The controlling system essentially includes an accumulatorin the forrn'nf :an expansible chamber, the accumulator being in :communication with the pump PP and auxilarypump Pa, the latter as is conventional being `used during engine starting. The oil pressure line between the pump PP and accumulator is .providedewith a by-pass O which leads to the lubricating rsystem to supply oil as may be required. The-controlling mechanism is in lthe 'form of 'azspoolvalve generally indicated by reference character '903, this valve being operated as lshown by a motor which rotates the valveparts tobringtthe necessary ports into communication with desired passageways to aecompiish lthe different `functions. This structure is conventional, as shown iin Fig. 5, and forms no part of the instant invention.

Thus it willbe Yseen that with the motor running at any necessary speed and with driving conditions requiring thatthe unit transmission be modiiied, the auxiliary fspeed reducing transmission .control is shifted 'either up or down as required. The `clutch (Fig. A6) between the unit transmission 'and the :auxiliary speed reducing transmission is of the overrunning type and incapable of propertmeshing except at synchronized speeds. The shafts ofthe unit transmission and. the auxiliary speed reducing transmission are synchronized automatically and without varying the motor speed. The shaft of the unit transmission is stepped downwardly by shifting the unit transmission control gradually, step by step, until the speed of this .transmission shaft will have reached the approximate speed of the auxiliary speed reducing unit. `By approximate speed is meant that the yspeed :shall have been reduced in the main `transmission unit to at least the speed. of the auxiliary :speed reducing unit shaft, at which time the clutch faces engage and from this point any lag in .the unit transmission shaft is prevented by'this clutch engagement, as the auxiliary shaft will carry the main shaft. When you slow down the .speed of the unit transmission output shaft, you are actually coasting. The movable part of the clutch will overrun the clutch of the driven shaft until the speeds are in synichroniza'tion; In that moment the clutch teeth will lay-on at the high side. The driver may, after the clutches :are synchronized, accelerate the engine and in 'so doing the engine and the drive member of the driven shaft will move in a positive direction and this will result in a torque reverse in the clutch which Aat this time will snap into full engagement with the gear teeth of the jaw clutch. From this point you select your main gear ratio and any yspeed on the unit transmission.

In the rst phase of the shift from the low to the high range, the output shaft of the auxiliary transmission is reduced .to a speed that is onefourth the speed of the unit transmission output shaft. This phase in the shift is to slow down the speed of the sun gear in the auxiliary transmission planetary and in so doing the ring gear of the same assembly will increase in speed and finally reach the speed of the auxiliary trans- 13 mission output shaft, and the clutch will automatically engage.

It will be observed that during this operation the output shaft is beingr driven not by the motor but by the vehicle due to its overrunning as the power plant is disconnected. During the operation synchronizing means between the main unit transmission and the auxiliary transmission, in which the overrunning of the vehicle begins at the time the power is disconnected, is utilized in synchronizing the transmission shafts. In shifting from high range to low range, the operation is exactly reversed and the operation is identical. When shifting from the low range to the high range, it will be necessary to decrease the speed of the unit transmission output shaft in order to increase the speed of the ring gear until it reaches the same speed. In order to accomplish this the unit transmission will be shifted to a lower speed.

What 1 claim is:

1. A transmission comprising, a casing, an input member connected to a multiple clutch nousing, plurality ci drive shafts connectable to said clutch housing, a plurality of series connected brake controlled planetary gear sets and an auxiliary speed reducing unit, two of said drive shafts being connected to two elements of the first of said brake-controlled gear sets, a third of said drive shafts being connected to an element of the last of said gear sets, said auxiliary speed reducing unit including a sun gear connected to an output shaft from said last of said gear sets, planet pinions in mesh with the sun gear and rotatably mounted on a carrier connected to a driven shaft, an orbit gear in mesh with said planet pinions and means for selectively locking said orbit gear to the transmission casing or to the driven shaft including a shiftable member slidably moved on the orbit gear by a fluid actuated annular piston, said shiftable member having an overrunning connection with the transmission casing or the driven shaft.

2. The structure of claim 1 characterized in that the orbit gear of the auxiliary speed reducf ing unit includes a hub extension mounted on the driven shaft and the shiftable overrunning connecting means is splined on said hub.

3. The structure of claim l characterized in that the overrunning connecting means between the transmission casing and the driven shaft is of annular form and the annular piston actuates.

14 means and annular piston are arranged concentrically about the hub.

6. The structure of claim 1 characterized in that the overrunning connecting means between the orbit gear of the speed reducing unit and the casing includes an annular clutch collar splined on a hub extension of the orbit gear, and the annular piston is cencentrically arranged thereabout and in spaced relation thereto, an anti-friction bearing assembly being interposed between the piston and collar and movable with the piston to transmit movement of the piston to the collar.

7. The structure of claim l characterized in that the casing is formed with an annular partition having clutch parts for association with the overrunning connection for locking the orbit gear of the speed reducing unit to the casing.

8. The substance of claim 1 characterized in that the annular piston is arranged in the casing and concentrically encloses the slidable and shiftable member having the overrunning connection with either the casing or driven shaft, a ball bearing assembly being interposed between the annular piston and slidable and shiftable member, the outer race of the bearing assembly being fixed in the inner wall of the piston and the inner race being slidably associated with the slidable and shiitable member, and cushioning elements interposed between the lateral faces of the inner race and adjacent faces of the slidable and shiftable member to resiliently impart thrust to the latter in either direction upon movement of the piston.

CARL EINAR SCHOU.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 252,537 Stewart Jan. 17, 1882 1,193,916 Norris Aug. 8, 1916 2,044,660 Alden June 16, 1936 2,084,522 Cotal June 22, 1937 2,130,632 Pollard Sept. 20, 1938 2,144,270 Palmgren Jan. 17, 1939 2,167,873 Burtnett Aug. 1, 1939 2,185,533 Burtnett Jan. 2, 1940 2,198,072 Banker Apr. 23, 1940 2,259,437 Dean Oct. 21, 1941 2,272,934 Cotal Feb. 10, 1942 2,292,633 G-riswold Aug. 11, 1942 2,326,994 Dufeld Aug. 17, 1943 2,351,746 Dreihaus June 20, 1944 2,397,883 Petersen et al. Apr. 2, 1946 2,408,008 Tipton Sept. 24, 1946 2,466,320 Lawrence Apr. 5, 1949 FOREIGN PATENTS Number Country Date 414,157 Germany May 25, 1925 428,779 Great Britain May 13, 1935 

